Multiple thermostat switch snapaction device



Feb. 7, 1939. L. M PERSONS 2,145,950

MULTIPLE THERMOSTAT SWTTCH SNAP-ACTION DEVICE Filed May 2l, 1936 /N VEA/TOE: A wei/VCE M, ffemws Patented Feb. 7, 1939 PATENT OFFICE MULTIPLE THERMOSTAT SWITCH SNAP- ACTION DEVICE Lawrence M. Persons, St. Louis, Mo., assignor, by mesne assignments, to Automatic Control Corporation, St. Louis, Mo., a corporation of Dela- Ware Application May 21, 1936, Serial No. 80,990

1 Claim.

The present invention relates to a switch mechanism and, in particular, to one adapted for use as a single or double-acting switch and in which certain parts are interchangeable.

s The invention further comprehends a switch having a magnet xed to the base and an armature therefor fixed to the movable switch arm. This armature may consist of one or two elements, both of which are identical and which 1o elements are selectively adapted to be brought into the eld of the magnet during the operation of the device.

It is an object ci the invention to provide a switch of this kind having a minimum number le of different parts.

it is a further object to provide a switch of this lrind having a snap-action means designed so that the same part can be assembled to cause it to act with a quickened motion in either of its g@ directions of travel.

It is a further object to provide such a snapaction means that, by the addition of a part identical to the part mentioned in the previous paragraph, can be made to act with a quickened 25. motion in both directions of its travel.

It is a further object to provide such a snapaction means including a switch blade, and one xed magnet, together with means adapted to be attached to the blade on either side of the mag- 3c net to cause the switch to operate With a snapaction in either direction of its travel.

In the drawing:

Fig. l is a sectional view of the switch as a Whole.

35 Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is a partial diagrammatic view showing a double-action switch closed in one position.

Fig. 4 is a view of the same switch in its other position. 1

40 Fig. En is a partial view of a single-acting switch that opens upon expansion of the diaphragm. Fig. 6 is a View of this switch in open position.

Figl is a view of a single-acting switch that 45 closes upon expansion of the diaphragm.

Fig. 8 is a View of this switch in closed position.

Fig. 9 is an end view of the snap-action mechanism.

Referring to Figs. 1 and 2, a U-shaped frame 50 element I0 is secured to a front plate II to form a housing. It is understood that around this housing, there may be placed an enclosing casing. A switch operating member here shown as comprising separable diaphragm elements I2, more 55 particularly described in my co-pending applicaver i9 is pivoted at 20 to the frame.

tion Serial No. 79,736 illed May 14, 1936, is supported on the frame by means of a nut I3 that secures the fluid containing tube I4 upon which the diaphragms I2 are mounted to the frame I0. It will be understood that the tube I4 extends 5 to the place, the heat of which is to be controlled by the switch and that it is full of a suitable iluid that expands upon heating.

Secured to the diaphragm is a stud I having a washer I6 xed thereon. The stud likewise 10 supports a sleeve I'I adjustably threaded onto the stud. An operating handle I8 having a dial thereon operates for adjustment of the sleeve in and out toward the diaphragms. A primary le- This primary lever is adapted to be engaged by the sleeve Il. A spring 2i coiled about the stud I5 holds the lever I9 against the sleeve Il or against a secondary lever 22. This secondary lever is pivoted to the frame at 23 and comprises the 20 switch blade element` A relatively light coil spring 24 maintains the secondary lever 22 in its most clockwise position. The secondary lever passes back across the stud and sleeve and has a hole therein to permit their passage. The sec- 25 ondary lever may have interposed therein an insulating portion 25 and a conducting portion 26. To this latter is brought a switch lead 2l. To the outer end of the secondary lever or switch blade 22 is secured an armature, comprising a 30 relatively non-permeable element at opposite ends of which may be securely relatively permeable plates 3l and 32. Lugs 33 and 34 extend from the ends of the members 30 through suitable holes in the members 3| and 32, and sup- 35 port the said members thereon, the lugs 33 and 34 being peened over for this purpose. It will be seen that the lug 34 also maintains the armature assemblage onto the switch blade. A double contact 35 is secured to the element 26. 40

A permanent magnet of the horse shoe type is secured to the frame member I0 by means of a screw 4I and a switch backing-plate 42. 'I'he screw 4I passes through suitable insulating elements 43 secured to the frame I0 and to the 45 switch backing-plate 42 to clamp the member 40 therebetween. A switch plate 45 of the type described in my co-pending application Serial No.

80,090, May 16, 1936, comprises a U-shaped plate, the connecting portion of which is bent at right angles to the respective legs. One

of the legs is secured to the switch backing-plate 42 and the other leg carries the relatively xed contact 46 to permit limited movement thereof.

A switch plate of this design permits a peeling apart of the contacts if they become welded together.

An vadditional switch backing-plate 50 is secured to the front plate II of the frame by means of a screw 5| that also forms a terminal screw for the switch. A switch plate 52 identical with the switchrplate 45 is secured to the switch backing-plate 5U and carries a relatively xed contact 53. The irst switch backing-plate 42 has an extension thereon to which the lead is attached. This lead goes to a terminal 56 on the front panel II.` The lead 2'| attached to the switch blade 26 goes to the terminal 51 also on the front panel The permeable elements 3| and 32 are identical. The switch may be made up with both of them, as is shown in Figs. 1 to 4 inclusive. It may be made up with only the permeable element 32, as shown in Figs. 5 and 6, or with onlyl the element 3|, as is shown in Figs. 'l and 8. The use of any of these combinations requires no new parts, because of the identity of these two permeable elements, the member 30 being used with any of the combinations, Where only one of the two permeable elements is used, the unused lugs 33 and 34 may be sprimg off, or left on, as desired. Where the switch employs only the element 32, the connecting element 30 may be eliminated, or cut down, if desired. Where the element 3| only is used, an impermeable plate 36 may be used at the opposite end of the connecting element 30 if desired to maintain the same spacing of the parts. This, however, is not essential.

The operation of the switch is as follows:

Referring to Fig. l, expansion ofY the diaphragms I2 shifts the stud I5 to the right, the stud carrying with it the sleeve I'I. The spring 2| maintains the primary lever I9 as far to the right as possible; and unless this lever I9 is stopped by the secondary lever 22, the spring 2| will maintain it in contact with the sleeve I'I. This movement of the primary lever, then, pivots the secondary lever about its pivot 23 to move this secondary lever in a counterclockwise direction. This moves the contact 35 away from the contact 46 and toward the contact 53. It will be seen that the expanding pressure of the diaphragm is transmitted through the spring 2|, which is a 'stii spring. When'the contact 35 meets the contact 53 and is stopped thereby, the primary lever I9 is necessarily stopped. Any further.expansion of the diaphragm, then, is absorbed by the spring 2|,

In adjusting the mechanism to operateat different temperatures, the handle I3 is turned to move the sleeve I1. 'I'his shifts the initial setting of the primary lever I9 and, consequently, changes the temperature at which the secondary lever 22 will be moved thereby, 'Ihis is described in detail in my co-pending application, Serial No. 79,736, above'mentioned. As is seen in the several views, the member 30 rides between the poles of the magnet 40 during movement of the switch. In the position shown in Fig. 3, the member 32 has been brought within theY eldof the magnet and the member 3| removed therefrom. 'In shifting to the position of Fig. 4, the Amember 32 is taken out of the field of the magnet and at a later part of the shifting movement, the member 3l comes into the ileld so that the iinal movement occurs with a snap-action to close the switch sharply. In reversing back to the position of Fig. 3, the converse is true, and the member 32 coming into the eld of the magnet snaps the contact 35 to the contact 46.

It will be seen that the switch plate 45 spaces the contact 46 slightly above the backing-plate 42, The switch plate 45 is of light resilient metal so that when the contacts are brought together, the plate yields and permits the contact 46 to move until stopped by the backingplate 42. As the switch. opens, and during the time the contact 46 moves from` against the backing-plate 42 to the normal position shown in the several views, very little resistance to its motion'is produced in the switch plate itself. It is during this period that the magnet is most eiective and applies most resistance to the openings of the contact. Beyond the position shown in the views, the switch plate itself sets up resistance to the following of the contact 35 by the contact 46, should they be welded together, the resistance being of such nature as to peel the .contacts apart with a minimum of eiort. It is, therefore, apparent that the resistance due to the switch plate is not brought into action until the armature element 32 is v partially free of the magnetic field, and the switch thereby obtains a running start to assist in peeling the contacts apart. It will be understood that the switch plate 52 is of identical construction and operation.

. The switch of Figs. 5 and 6 operates against a single contact that opens upon rise of heat. Such a switch would be used in a heating system. 'Ihe switch of Figs. 7 and 8 closes upon rise of heat and such a switch would be used in a refrigeration system. All of these switches operate with the magnet and the same construction, save for the elimination of the unnecessary switch elements and the unused amiature plate. By thus designing the' switch, a minimum number of parts is required and the assembling operations are greatly simplified.

The switch is particularly applicable where diaphragm or bellows expanding means are used, with a so-called solid charge (i. e., free of gas). In such systems, any heat changes cause expansion of the liquid, which is relatively incompressible, whereby the action is positive.

Furthermore, the movement produced is relatively small.

What is claimed is:

In a mechanism of the kind described, a maget, a movable blade, an armature mechanism adapted to cooperate with said magnet to give either two-way or one-way snap actionto said blade, s'aid mechanism comprising a connecting memb'er ladapted to cross said magnetic ileld and having a lug projecting from each end thereof, and a pair of identical armatures each having a hole to receive one q1' the lugs by means of which said armatures may be attached to' the connecting member, and said blade likewise having an opening through which one of said lugs may extend whereby one or both of said armatures may be secured to said blade to eilect snap action thereof in either one or both directions.

LAWRENCE M. PERSONAS. 

